[Paul Ross]

Boost-phase is the EASIEST , MOST VULNERABLE target. (at least from orbit or very close border) Far easier than mid-course or re-entry. And we have successfully shown repeated capability to intercept in mid-course, and with the old (1960-70s era)--yet utterly AWESOME!-- Sprint missile technology...a consistent ability to hit re-entry vehicles coming in at Mach 16. Should have just deployed a few of these around every major U.S. city, and strategic site. Net cost would have been far less today than SDI ( a pure research program) has been to date....

[elbucko]

Sprint missile technology...a consistent ability to hit re-entry vehicles coming in at Mach 16.

Put some in submarines. The sub, is by far, the best platform for offensive and defensive missiles.
( And no, I was Army!)